This application claims the benefit of the Australian application PQ 2975 filed Sept. 20, 1999 and the international application PCT/AU00/01066 filed Sept. 8, 2000.
The present invention relates to a gaming machine of the type known as a slot machine or fruit machine. Certain types of machines have a series of rotatable reels each of which displays a series of symbols or a video simulation of such a mechanism while other types of machines are arranged to play video simulations of card games or other types of wagering games, such as bingo or keno. More particularly, the invention provides an improvement to a game played on such a machine.
Players regularly playing gaming machines quickly tire of particular games. Therefore, it is necessary for manufacturers of these machines to develop inventive game features which add interest to the games provided on such machines in order to keep the players entertained and willing to continue to play the games.
Gaming machines of the type described are particularly well known nationally and internationally. Substantial amounts of money are wagered on these machines. In Australia, in the state of New South Wales and other states, there is a growing tendency to legalize the use of gaming machines by licensing operators with resulting revenue gains being achieved through license fees and taxation of moneys invested. The licensed operation of gaming machines is the subject of state legislation and regulation. Amongst the items regulated is the maximum percentage payout for a gaming machine. For example, a minimum of 85% of moneys invested must be returned as winnings, and manufacturers of gaming machines must therefore design their machines around these regulatory controls.
With the growth that has occurred in the gaming machine market, there is intense competition between manufacturers to supply the various existing and new venues. When selecting a supplier of gaming machines the operator of a venue must pay close attention to the popularity of various games with their patrons. Therefore, gaming machine manufacturers are keen to devise games which are popular with players as a mechanism for improving sales and for maintaining player interest. In this regard, various strategies have been tried in the past to make games more enticing to players including an increase in the number of physical reels or video simulations of such reels. It has become almost standard practice for a gaming machine to have five spinning reels or video simulations thereof.
Players using these machines have become used to these types of games and have come to expect certain things from the games. For example, players expect that every standard symbol on each reel will pay a prize for combinations of three or more of that symbol, usually on a pay line. Also, players expect not to have to play too long without being rewarded, whether by means of a large or small amount. Further, players expect that a five of a kind win is quite achievable.
Current methods employed in game design make it extremely difficult to develop games having more than five reels (a reference to xe2x80x9creelxe2x80x9d is to be understood as including a video simulation of such a reel) and still maintain the expectation of players without altering the maximum percentage payout for the machine.
For reel strips of a fixed length, a player is much less likely to get a six of a kind combination on a six reel game than a five of a kind combination on a five reel game. As a result, a six reel, six of a kind win is less achievable than a five of a kind win for a five reel game.
Should the frequency of six of a kind wins be increased by manipulating the length of the reel strips and/or reducing the prizes, the frequency of three, four and five of a kind wins would be increased proportionally. This would have the result of increasing the overall theoretical percentage payout of the machine leading to losses for the venue. Removing the three of a kind win is also not an acceptable solution as players have built up an expectation of receiving a win for such a combination.
According to the invention, there is provided a gaming machine which includes:
a display means including a plurality of display positions for displaying combinations of symbols; and
a control means for controlling operation of the machine, the control means including a random number selection means for selecting the symbols to be displayed at each display position, the chance of a particular symbol being selected by the control means, independently of a player of the game, to appear at a predetermined display position being dependent on whether or not that particular symbol has been selected by the control means to appear at at least one other display position.
The invention has particular application in gaming machines having video simulations of spinning reels. For ease of explanation, the invention will be described with reference to that application but those skilled in the art will appreciate that the invention could be equally applicable to other types of gaming machines such as those which use simulations of playing cards or balls.
Further, for ease of explanation, the gaming machine will be described with reference to a six reel display. Once again, it will be appreciated that any number of reels could be employed in the display of the gaming machine. These reels are referred to below as the first, second, third, fourth, fifth and sixth reels. The particular symbol may be a special symbol, a substitute symbol a wild card-like symbol or some other special symbol such as a xe2x80x9cscatterxe2x80x9d symbol, a feature trigger symbol, a xe2x80x9ctop awardxe2x80x9d symbol, or the like. Although the invention is applicable with any chosen symbol, for ease of explanation the operation of the system will be described with reference to a substitute symbol.
The random number selection means may map a number to each position on each reel such that the symbols that appear in said predetermined display position are those that appear on the reels in the positions corresponding to the random numbers. The substitute symbol may thus have random numbers associated with the positions in which it appears on the reels.
A random number selected may be dependent on the number of symbols that can possibly appear in said predetermined display position, the control means being operable to change a set of possible outcomes of the symbol to be displayed at further, predetermined display positions dependent upon the position already selected to be displayed at said at least one other display position. Where the game is a spinning reel game, the random number selected may thus be dependent on the length of the reels and the control means may be operable to change the set of possible outcomes of one or more further reels dependent upon the symbol already selected for at least one other reel. In so doing, the probability of the substitute symbol appearing at the required display position on certain of the reels is dependent upon whether or not that substitute symbol has already been selected to appear at the display position of one or more of the other reels.
In particular, the invention is intended to increase the possibility of obtaining four of a kind of the substitute symbol which appears only on reels two, three, four and five of a six reel game and, in so doing, increasing the possibility of five or six of a kind wins of the substitute symbols in combination with other symbols on reels one and/or six. This may be achieved by decreasing the number of symbols on reels two, three, four and five to increase the frequency of four substitute symbols. However, this would then also increase the frequency of two and three substitute symbols. By means of the use of the re-mapping or re-selection process associated with the reels carrying the substitute symbols, the frequency of five and/or six of a kind wins are increased without proportionally increasing the frequency of two or three of a kind wins.
Thus, once a position has been chosen for the second reel via the random number selection means of the control means, the position may be evaluated to determine whether or not the substitute symbol will appear within the display positions of the second reel. If so, the game is played normally, without any further re-selection or re-mapping occurring. If, however, the substitute symbol is not to appear within the display positions of the second reel, re-mapping or re-selection occurs in respect of reels three, four and five to decrease the probability of occurrence of the substitute symbol within the display positions of the respective reels.
In another embodiment of the invention, the random number selection means may be governed by two sets of possible outcomes associated with each display position for further display positions, the sets of possible outcomes to be used for said further display positions being dependent oil the symbol already selected to be displayed at said at least one other display position. Once again, in the case where the game is a spinning reel game, the sets of possible outcomes for said further display positions may be reel strips of differing lengths for each of said further display positions.